Plants biennial
or perennial herbs or shrubs (annuals elsewhere). Leaves basal and/or opposite
or alternate along the stems, sessile to long-petiolate. Stipules absent or
inconspicuous, then herbaceous, attached along a line or slender ridge, the
adjacent stipules of the leaves at each node fused into a single triangular to
depressed-ovate structure. Leaf blades unlobed or less commonly pinnately
lobed, variously shaped, the margins usually scalloped or toothed.
Inflorescences racemes (sometimes spikelike) or panicles of usually numerous
flowers, at least the lower nodes subtended by bracts, inconspicuous bractlets
sometimes also present below each flower. Flowers perfect, hypogynous. Calyces
actinomorphic or nearly so (zygomorphic elsewhere), 4- or 5-lobed, persistent
at fruiting. Corollas actinomorphic or zygomorphic and sometimes bilabiate,
variously colored, 4- or 5-lobed, the tube variously short to long. Stamens 4
or 5, alternating with the corolla lobes, the filaments attached in the corolla
tube (sometimes near its base), sometimes unequal, the anthers exserted or not,
attached near their midpoints or sometimes fused to the filament tips for 1/2
or more of the length, often appearing U-shaped or 1-locular, yellow or orange.
Staminodes absent or (sometimes in flowers with 4 fertile stamens) present,
then well differentiated from the fertile stamens. Pistil 1 per flower, of 2
fused carpels. Ovary 2-locular (sometimes appearing 4-locular elsewhere), with
numerous ovules, the placentation axile. Style 1, often persistent at fruiting
(but sometimes shriveled or shed toward the tip), the stigma 1, variously
shaped, entire or 2-lobed. Fruits capsules (drupes or schizocarps elsewhere),
dehiscent longitudinally from the tip. Seeds numerous, minute. About 52 genera,
about 1,680 species, worldwide.

Perhaps no other
family in the traditional Englerian classification has undergone as profound a
reevaluation as the Scrophulariaceae. In the traditional broad sense, the
family once included nearly 200 genera and about 4,000 total species. However,
a number of botanists had already noted the extreme morphological diversity
within the group and the difficulties involved in using morphological
characters to separate the Scrophulariaceae from some related families, such as
the Acanthaceae, Bignoniaceae, Globulariaceae, and Orobanchaceae (Cronquist,
1981). The application of molecular data from selected DNA marker sequences has
had a profound effect on the classification of families and orders across the
angiosperms and has greatly altered the classification and circumscription of
the groups associated with the Scrophulariaceae, Lamiaceae, and related
families. As presently circumscribed, a very large order Lamiales includes the
families formerly included in that order, as well as those previously
segregated into Bignoniales and Scrophulariales by some botanists (see Judd et
al. [2008] for a brief review). As researchers began to sample a larger suite
of species within the various groups contained in the Lamiales, it soon became
apparent that the Scrophulariaceae, as traditionally treated, was an unnatural
group (as reviewed by Tank et al. [2006]). This has resulted in the break-up of
the Scrophulariaceae into seven to eleven families, but the number of families
and the generic limits of each have not yet become fully stabilized (Angiosperm
Phylogeny Group, 1998, 2003, 2009). Additionally, a few groups formerly
classified as distinct families have been included within some of these
recently recircumscribed families. The introduced genus Buddleja was not
known to be a member of the state’s flora when Steyermark (1963) completed his
volume. Many botanists have treated it in the segregate family Buddlejaceae
(Leeuwenberg and Leenhouts, 1980; Cronquist 1981, 1991; G. K. Rogers, 1986;
Norman, 2000), but it currently is considered by most botanists to belong in
the Scrophulariaceae.

A summary of the
current familial placement of the various genera included by Steyermark in the
Scrophulariaceae is presented below, along with other genera that are now
classified into this group of families. Members of the Acanthaceae,
Bignoniaceae, Martyniaceae, and Oleaceae, families in the Lamiales whose circumscriptions
for the genera present in Missouri have not changed since Steyermark’s (1963)
time, are not included in the list.

In its
diminished current form, the family Scrophulariaceae has relatively limited
economic importance. Members of several genera are cultivated as ornamentals,
including Buddleja and Verbascum. Conversely, in some parts of
the United States, species in these genera are considered troublesome weeds.
Many species in the family are considered at least mildly toxic to livestock
and a few genera contain plants that have been used medicinally.

In addition to
the taxa treated below, Steyermark (1963) also included a report of Limosella
aquatica L. (common mudwort; Pl. 559 a, b) from Missouri. He noted that the
inclusion of this species was based on a single historical voucher specimen
collected by B. F. Bush in Jackson County, but did not cite a collection number
or herbarium where the specimen was accessioned. Palmer and Steyermark (1935)
had stated that the plant occurred on sand bars of the Missouri River (as L.
subulata E. Ives), but gave no other clues to the location of a voucher.
Pennell (1935), in his study of the eastern temperate North American
Scrophulariaceae, did not cite Missouri in the range of any species of Limosella,
and Missouri has not been cited as part of the species range in other
publications. During the present research, despite diligent searches, no
specimens were discovered to support the inclusion of Limosella in the
Missouri flora, and it is thus excluded for the present. Limosella aquatica
is widespread but of sporadic occurrence in Europe and Asia, and in the New
World from Canada south to South America. In the United States it is known from
most western states eastward to Minnesota and Nebraska. It is a submerged or
emergent aquatic that likely is spread by mud on the feet and feathers of
migratory waterfowl. The species is inconspicuous; plants are rarely 15 cm
tall, although the stems are stoloniferous and creeping. The leaves occur in dense
tufts at the rooted stem nodes and consist of a long, slender petiole
terminating in a short, lanceolate to elliptic blade. The inconspicuous flowers
are solitary at the tip of a stalk that is shorter than the leaves. Corollas
are 3–4 mm long, more or less actinomorphic, with a slender tube and 5 short
lobes, white or pale pinkish- to purplish-tinged. Botanists who do field work
in wetlands that are stopover points for ducks and other migratory waterfowl
should be alert for new records of this diminutive member of the
Scrophulariaceae.